ADXL335

The ADXL335 is a triple axis accelerometer with extremely low noise and power consumption – only 320uA! The sensor has a full sensing range of +/-3g. Looking to buyor find the datasheet. Look here.
I used the breakout board from sparkfun which is an easy way to connect it to the arduino. There is no on-board regulation, provided power should be between 1.8 and 3.6VDC. I cheated and still used the power pins from the arduino to power the board at 5v. The board comes fully assembled and tested with external components installed. This includes a 0.1uF capacitors set the bandwidth of each axis to 50Hz.

To test the functioning of the adxl335 accelerometer i used the program below and connected it to the arduino like this. Basically the VCC and GND pins are generated by the arduino analog PINS 4 and 5. Of course the software should take care of that and power the VCC to +5V and the GND to GND or else it will not work. Below are some accelerometer readings collected by the positioning the y-axis of an ADXL335 2g accelerometer at various angles from the horizontal level. If each axis is placed in the same plane the values should be the same. Of course if you alter the sensitivity the values will be different. With the axis horizontal (i.e. parallel to ground or 0°), the accelerometer reading should be around 512, but values at other angles will be different. For different accelerometer (e.g. the ADXL302 5g one) the values will also be different. B ecause you know that straight down the accelerometer should read 1g you can also calibrate the values to g.